The previous Chancellor George Osborne originally planned to wipe out the deficit in 2015

Ex-Chancellor George Osborne originally planned to wipe out the deficit in 2015.

Torsten Bell, director of the Resolution Foundation, said: “The Chancellor has been handed a massive downgrade to expectations for how fast Britain’s economy can grow.

“The result for the public finances is grim.

"But the outlook for family finances however is worse.”

Overall, the economy is expected to grow by 5.7 per cent between now and 2022 – compared with a forecast 7.5 per cent rise in March.

OBR chief Robert Chote dismissed claims he was being gloomy about Brexit – saying the EU divorce wasn’t a factor in the growth downgrade.

He blamed a “historical” change to economists’ predictions about productivity – output per hour.

Compared with an average growth of 2 per cent before the crisis, productivity is now expected to rise from 0.9 per cent this year to just 1.2 per cent in 2022.

OBR exec and former Bank of England deputy governor Charlie Bean said Britain like many advanced nations were suffering from the longest sustained period of weak productivity growth since before the Industrial Revolution.

He said the advent of Artificial Intelligence and genetic engineering could improve efficiency while interest rate hikes would “weed out” inefficient firms.